John Chrysostom

But wherein are they earnest, and vigorous? In the things forbidden. For, "all their works they do," He saith, "to be seen of men." These things He saith, accusing them in respect of vainglory, which kind of thing was their ruin. For the things before were signs of harshness and remissness, but these of the mad desire of glory. This drew them off from God, this caused them to strive before other spectators, and ruined them. …

Homily on the Gospel of Matthew 72 ↗

Desert Fathers

Three brothers once came to a hermit in Scetis. One of them said to him, 'Abba, I have memorized the Old and New Testaments.' But the hermit answered, 'And you have filled the air with words.' The second said to him, 'I have written out the Old and New Testaments with my own hand.' But the hermit said, 'And you have filled the window-ledge with manuscripts.' The third said, 'The grass is growing up my chimney.' But the hermit answered, 'And you have driven away hospitality.'

The Desert Fathers, Sayings of the Early Christian Monks ↗

Jerome

For they enlarge their phylacteries and magnify their fringes. They love the places of honor at banquets, the chief seats in the synagogues, greetings in the marketplaces, and to be called Rabbi by men. Woe to us, miserable ones, to whom the vices of the Pharisees have been passed on. When the Lord gave the commandments of the Law through Moses, He added at the end: Bind them upon your hand, and they shall be before your eyes (Deut. VI, 8). …

Commentary on Matthew ↗

Thomas Aquinas

And all their works they do to be seen by men. Here he sets forth their intention; and he does two things. First, he reveals their intention; secondly, he warns the disciples to avoid them. And first he sets forth their intention; secondly, he explains it, at for they make their phylacteries broad, etc. What is the reason why they say and do not? Because they are incorrigible. Now the reason why a man is difficult to correct, or incorrigible, is that he seeks his own glory. …

Commentary on Matthew ↗